1. Field of the Invention
The present invention relates to an apparatus for selecting among multiple sources of flush water for a toilet, such as a marine toilet, while avoiding contamination of the flush water sources. The multiple sources of flush water for a marine toilet may include potable water and may include seawater. For the purposes of this application, the term "seawater" means any water in which the vessel floats, whether the water is lake or salt.
2. Description of the Prior Art
The design of sewage systems for use aboard marine vessels presents a tension between aesthetics and space limitations. Odor is always an issue concerning sewage disposal, and the use of potable water for flushing waste from toilets is preferred to other flushing media such as recirculated wastewater or seawater due to the lower potential for odor presented by potable water. However, space to store potable water is scarce on a marine vessel. It is desirable, therefore, to use a source other than potable water to flush wastes from a marine toilet while a vessel is away from port. In port, a vessel may be connected to a land-based potable water system and the need to conserve potable water is reduced.
The present invention provides that the flushing medium readily may be selected either as seawater or as potable water. The invention allows the avoidance of unnecessary odor in port, where an ample supply of potable water is available, and allows a vessel to avoid storage of unnecessary quantities of potable water while away from port.
Toilets used in marine vessels such as personal yachts and pleasure craft typically utilize either manual or electrical pumps to supply a source of flush water. Popular models of electrically operated marine toilets include (but not limited to) the Atlantes.TM. and Crown Head II.TM. and rely upon flush water supplied to the toilet under pressure by an electrically operated pump. Manual toilets may use a manually operated piston pump to pump seawater into the toilet and sewage out of the toilet. In the piston pump toilets, one side of the pump piston is used to supply a positive pressure to pump the seawater into the toilet bowl. The second side of the pump piston is used to supply a negative pressure to the sewage in the toilet bowl, clearing the bowl and allowing the sewage to flow to a holding tank.
Toilets used in marine vessels generally use either potable water or seawater to flush waste from the toilet bowl and into holding tanks or treatment system. The flush water and the collected wastes are removed from the holding tanks when the vessel is in port. The prior art toilets and marine sewage systems do not allow selection between seawater and potable water as flushing media. The prior art toilets and marine sewage systems therefore are susceptible to the odor and potable water storage deficiencies discussed above.
Several devices have been developed to address these problems. U.S. Pat. No. 3,593,346 to Katona issued Jul. 20, 1970 provides for the selectable use of recirculated sewage or potable water as flushing media for vehicle toilets. Recirculation of sewage, while space-efficient, exacerbates the problem of odor. The 346 Katona patent does not provide for selecting either seawater or potable water as the flushing media.
U.S. Pat. No. 3,611,447 to Howard, issued Oct. 12, 1971 addresses the odor problem caused by recirculated sewage used as flush water. Howard provides two sequential toilet bowls separated by valves. The first bowl is flushed with potable water and the second is flushed with recirculated sewage. Howard does not provide for selecting either seawater or potable water as the flushing media.
U.S. Pat. No. 3,780,383 to Katona issued Dec. 25, 1973 is based on a divisional application and includes the same disclosure as the 346 Katona patent. The 383 Katona patent teaches a folding toilet with a bowl that drains into a second bowl when the toilet is folded. Both bowls are flushed selectively with treated wastewater or "running water." The 383 Katona patent does not provide for selecting either seawater or potable water as the flushing media.
U.S. Pat. No. 3,815,159 to Delaney issued Jun. 11, 1974 and related U.S. Pat. No. 3,927,425 to Delaney issued Dec. 23, 1975 reveal a sewage system for marine vessels using recirculated treated sewage for the flushing of toilets. The Delaney patents do not provide for selective use of seawater or potable water as the flushing media.
U.S. Pat. No. 4,433,443 to DeGraw issued Feb. 28, 1984 reveals a marine sewage system using seawater for flushing of toilets. A removable filter cassette collects solid wastes from the seawater and the contaminated seawater is treated by an "electrolytic cell." The treated seawater is then discharged to the sea. DeGraw does not provide for selection between seawater and potable water for the flushing of toilets.
U.S. Pat. No. 4,454,613 to Palmer reveals a sewage system for travel trailers and allows flushing of toilets using either potable water or non-sewage wastewater. Palmer does not teach selectable use of seawater or potable water for flushing of toilets.
U.S. Pat. No. 5,711,038 to Neithammer dated Jan. 27, 1998 reveals a toilet for vehicles where solid wastes are separated from liquid wastes, the liquid wastes are disinfected and used for flushing toilets. Neithammer does not teach selectable use of seawater or potable water for flushing toilets.
The apparatus of the present invention offers advantages over the prior art. The prior art marine sewage systems neither teach nor suggest the selectable use of seawater or potable water as a flushing media. The prior marine sewage systems do not teach or suggest the use of the valving and related system of the present invention to allow selectable interconnection of seawater systems and potable water systems for the flushing of toilets while avoiding contamination of either system.